Seat back



FIG. 1 is a perspective view of a seat back, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof, taken from the left of FIG. 2;

FIG. 5 is an opposite side elevation view thereof, taken from the right of FIG. 2;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

I claim, the ornamental design for seat back, as shown and described. 